Dental tool with power operated brake



Se t. 11, 1962 J. R. MlTTHAUER ETAL 3,052,984

DENTAL TOOL WITH POWER OPERATED BRAKE 2 Sheets-Sheet 1 Filed June 17, 1960 INVENTORS Jo /y P. M rr/Mua Array/my Sept. 11, 1962 J. R. MITTHAUER EI'AL 3,052,984

DENTAL TOOL WITH POWER OPERATED BRAKE 2 Sheets-Sheet 2 Filed June 17, 1960 i w 0U. m m 3., 7 A m M M 0 2% Y B E btates aren't 3,@Z,84 Patented Sept. ll, 1932 h h s 1% 3,052,984 DENTAL T0912 Wii l-i POWER OPERATED BRAKE Iiohn R. Mitthaner, 630 Victory Blvd, and Rudolph Vetere, 49 Sheradau Ave, both of Staten Island, NE. Filed dune 17, 196i), Ser. No. 36,940 Qiaims. (Cl. 3'227) This invention relates to portable tools, especially dental handpieces, which include a cutting implement, a drill bit, or some other device. More particularly, the invention relates to the provision of power operated brakes for such tools.

One object of the present invention is to provide a power operated brake for a tool of the type indicated, which has provision for rendering the driving means of the tool inoperative concurrently with the operation of the brake.

A further object is to provide a portable or dental tool which is operated by fluid pressure with a power operated brake which has provision for diverting the fluid pressure from the rotatable member of the tool to the brake for the operation thereof concurrently with the stopping of the supply of fluid pressure to the rotatable member.

Another object is to provide a tool of the type indicated with a power operated brake which is operated by fluid pressure.

A further object is to provide a tool of the type indicated with a power operated brake which is operated by electrical means.

Another object is to provide a tool of the type indicated with a power operated brake which employs the impact force of a stream of fluid pressure on the rotatable member of the tool to prevent or stop the rotation thereof.

The above and other objects, features and advantages of this invention will be fully understood from the following description considered in connection with the accompanying illustrative drawings of the presently preferred embodiments of this invention.

In the drawings:

FIG. 1 is a side elevational view of a dental handpiece in accordance with the present invention;

1G. 2 is a longitudinal sectional view, on a larger scale, with portions cut away illustrating a part of the dental handpiece of FIG. 1;

P16. 3 is a sectional view, on a larger scale, of part of a dental handpiece in accordance with another embodiment of the invention and illustrates more or less schematically a control means for the tool;

FIG. 4 is a sectional view on a larger scale of part of a further embodiment of the invention;

FIG. 5 is a sectional view taken on line 55 of FIG. 4; and

FIG. 6 is a sectional view, on a larger scale, of part of another embodiment of the invention and illustrates more or less schematically the control means therefor.

Referring now to the drawings in detail and particularly to FIGS. 1 and 2, the portable tool, here shown as a dental handpiece 10, comprises a tubular handle 12 which has a longitudinally extending passageway 14 for transmitting a supply of fluid pressure, for example air, from conduit 16 at the lower end of the tool to the upper end of the tool for imparting rotary movement to the cutting implement or dental burr 18 mounted at said upper end of the tool. The upper end of the tool is provided with a housing or casing 29 which mounts a cutting implement assembly 22 which has provision for mounting the dental burr 18 therein for rotary movement. Said assembly includes a cylindrical casing 24 and a rotor 26 which, as herein shown, is a fluid pressure operated turbine wheel. The turbine wheel 26 is mounted on a shaft 28 and is connected thereto so that the turbine wheel and shaft rotate as a unit. The shaft is supported in bearings 30 whose outer races are press fitted to casing 24-. The shaft 28 of the turbine is hollow and is provided with internal threads so that a chuck 32 may be screwed therein, said chuck being adapted to releasably receive the cutting tool 18. A plug 34 is screwed into housing 20 for retaining assembly 22 within said housing. Plug 34 also functions to retain a brake device 36 within housing 20, which will be fully described hereinafter.

During the operation of the tool, pressure in the form of a fluid stream is transmitted through passageway 14 in the handle 12 of the tool and flows longitudinally of the tool to casing 24 which encloses the turbine wheel. The casing is provided with an aperture 38 which constitutes a fluid inlet permitting the fluid pressure from passageway 14 to enter the interior of casing 24 and drive the turbine wheel 26 which causes the dental burr 18 to rotate. In the case of a pneumatically operated tool, the air which supplies the fluid pressure for driving the turbine wheel 26 is preferably provided with oil in the form of a mist which deposits on the bearings 30 and lubricates the bearings as the air passes from the turbine wheel through the bearings and out of the tool via openings at} in housing 29 or passageway 42 in brake shoe member 44 of the brake device 36. Passageway 42 in the brake shoe member permits a pin to be inserted therethrough for the removal of the cutter 18 from its chuck 32, the pin passing through a central aperture 45 in the chuck. It will be understood that handle 12 is also provided with a water passageway (not shown) for transmitting water to the dental burr 18 for the cooling thereof and the cooling water is transmitted to said dental burr through openings 4% in the housing 2d.

The brake member 44 is mounted for axial movement in a centrally located aperture 56 which is provided in plug 34. A flexible diaphragm 4-8 of a suitable material is connected to the brake member 44 near the inner end 59 thereof, said inner end projecting beyond the inner surface of the diaphragm, as shown. The peripheral edge of the diaphragm is gripped between a ring 52 and plug 34, as shown, to mount the brake device 36 within housing 20 of the tool, as previously indicated. It will be apparent from the foregoing that brake shoe member 44- is free to move axially toward shaft 28 of the turbine wheel so that end 5t of the brake member can frictionally engage end 54 of the shaft and prevent said shaft from rotatmg.

The upper part of handle 12 or the neck portion 55 of the tool it is provided with a passageway 56 and plug 34 is also provided with a passageway 58 which is connected to passageway 56 and is also connected to a chamber which confronts the outer surface of diaphragm 48. A manually operated valve 62 is mounted on the neck portion 55 of the tool and has a passageway 64 extending therethrough. A spring 66 biases valve 62 outwardly of the handle so that passageway 64 does not normally communicate with either passageway 14 or passageway 56. Spring 66 is suitably secured to the handle and the valve. 0 rings 63 are provided to prevent any leakage of fluid around the valve.

From the foregoing it will be apparent that when the operator or dentist desires to stop the rotation of cutting implement 18, the dentist presses his thumb or finger against valve 62 causing said valve to move inwardly of the handle connecting passageway 64 with passageways 14- and 56. This action immediately cuts off the flow of fluid to turbine wheel 26 and bypasses said fluid into chamber as via valve passageway 64, passageway 55 and plug passageway 58. The fluid pressure in chamber 69 causes axial inward movement of brake shoe member 44 causing the inner end 50 thereof to engage the end 54 of the turbine shaft 28, thereby braking the rotation of said shaft. It is to be observed that the same fluid pressure which operates the turbine wheel also opcrates the brake device 36 and concurrently with the rendering of the turbine wheel inoperative by the actuation of valve 62, the brake is actuated for the braking operation. The fluid in chamber 59 escapes from the tool via the space between the outer surface of brake shoe member 44 and aperture 46 in plug 34. Upon releasing valve 62 it moves outwardly under the biasing force of spring 66 so that fluid is again transmitted through passageway 14 to the turbine wheel for the operation of the cutting implement 18. As the fluid leaves housing 20 it passes into chamber 79 which confronts the inner surface of the diaphragm 48 and the fluid pressure exerted on said inner surface causes brake shoe member 44 to move axially outwardly so that ends 59 and 54 of the brake shoe and shaft, respectively, are disengaged. It is to be observed that this disengaging movement occurs simultaneously with the introduction of air to the turbine wheel for the operation thereof.

Referring now to FIG. 3, there is shown another embodiment of the invention which is similar to the handpiece shown in FIGS. 1 and 2 but is provided with a foot operated control mounted remotely from the handpiece in lieu of the finger operated valve 62 mounted on the neck of the handpiece. More particularly, a solenoid operated valve 72 controls the flow of fluid pressure through passageways 14 and 56 in the body of the handpiece. Suitable conduits 74 and i6 transmit fluid pressure to passageways l4 and 56, respectively, said fluid pressure being supplied to the valve from a source not shown, via conduit '78. A pair of wires 34 and 32 are connected to the coil 84 of the solenoid and to a suitable source of current, not shown, and a foot operated electrical switch 86, which is normally open, is in series with the coil of the solenoid.

From the foregoing it will be apparent that when the operator or dentist desires to stop the rotation of the cutting implement 18, the dentist closes switch 86 by pressing his foot down on said switch causing the solenoid coil to be energized which moves the piston 87 in valve 72 downwardly, compressing spring 8%,- cutting off the flow of fluid pressure to conduit 74, via port 91, passageway 64, and port 93, and simultaneously transmitting the fluid pressure from conduit 78 to conduit 76, via port 91, passageway 64, and port 95, thereby actuating brake device 36 for stopping the rotation of the turbine wheel 26, in the exact same manner as previously described with respect to the hand tool illustrated by FIGS. 1 and 2. When the dentist releases the pressure of his foot on the switch 86, said switch opens to de-energize the solenoid of the valve and the piston in the valve moves back to its original position, under the biasing force of spring 89, which permits the flow of fluid pressure again to the turbine wheel for rotating the cutting implement 18.

Referring now to FIGS. 4 and 5, there is shown another embodiment of the invention which includes a fluid pressure operated brake device which may be actuated by a manually controlled valve mounted on the body of the handpiece, as shown in FIGS. 1 and 2, or may be actuated by a foot operated switch, as shown in FIG. 3. More particularly, end 54 of shaft 28 of the turbine Wheel 26 is provided with an extension 88 which has opposite flat surfaces 90 which rotate with the shaft and are adjacent passageway 58 in plug 34'. Accordingly, when a stream of fluid or air flows from passageway 58 it is directed against the flat surfaces 90 of the rotating shaft and the impact force of the stream on said surfaces causes said shaft to stop rotating. It will be understood that the stream of pressure fluid impinges on either of the surfaces 90 depending upon which surface is closest to passageway 58 when the valve is actuated for the braking operation. It will also be understood that the braking action of the stream on the shaft of the turbine may be actuated by the control means shown in FIGS. 2 or 3, as previously mentioned.

The handpiece 1!; of FIG. 6 is provided with a brake device 36 which is operated electrically rather than by fluid pressure means, as previously described with respect to the handpieces of FIGS. 1 through 5. Brake device 36' comprises a movable brake shoe member 44 which constitutes the core of a solenoid having a Winding 92. The winding is mounted in a ring 52 and the ring and winding are retained in the housing 20 by the plug 34" which is screwed into one end of the housing. A spring 94 which is secured to the plug 34" and the core or brake shoe member 44 biases said member away from the shaft 23 of the turbine wheel so that inner end 59 of the brake shoe member and the end 54 of the shaft are disengage-d from each other. A pair of insulated wires 96 and 98 extend through the body of the handpiece and are in electrical contact with insulated conductors 1% and 162, respectively, which are provided in ring 52'. Conductors 1% and 132 are connected to,the ends, respectivel of the electrical wire constituting winding 92 of the solenoid.

A solenoid operated valve 72' controls the flow of fluid to passageway 14 in the handle of the handpiece, via conduits 78 and 74, in a similar manner as previously described with respect to FIG. 3. In series with the winding 84 of the solenoid operated valve 72' is the normally open switch 86 which may be operated by the pressure of the foot. Wires 104, 166 and 108 complete the series circuit through winding 84, switch 86, wires 96 and 98 and conductors 1% and 1&2. Wires 1G4 and 136 are connected to a suitable source of current.

From the foregoing it will be apparent that when the dentist desires to stop the rotation of the cutting implement 18, he applies pressure with his foot to switch 86 closing said switch which completes a circuit through coil 34 of the solenoid operated valve 72' and the coil is energized causing the piston 87 in the valve 72 to move downwardly compressing spring 89 and shutting off the fluid pressure to the turbine wheel, which is supplied via port 91, passageway 64 and port 93. Concurrently with the closing of the valve, a circuit is completed through the winding 92 of the solenoid operated brake 36' which energizes said winding causing brake shoe member or core 44' to move inwardly so that inner end 50 thereof frictionally engages end 54 of the turbine shaft 28 and breaks the rotational movement thereof. When switch 86 is opened, upon removal of the pressure of the foot on said switch, the open switch de-energizes coil 84 of the solenoid operated valve 72 and simultaneously de-energizes coil 92 of the solenoid operated brake 36. The piston in the valve moves back to its original position, under the biasing force of spring 89, so that the valve opens permitting the flow of fluid through passageway 14 to the turbine wheel for operating the cutting implement. Spring 94 moves the brake shoe member 44 outwardly back to its original position where ends 50 and 54 of the brake member and shaft, respectively, are disengaged. If desired or as required, a cap 104 of a suitable material which is non-conductive may be provided to cover the end of housing 20' and thereby assure that the part of the patients mouth, in the case of a dental handpiece, does not come in contact with the metal core 44' of the solenoid operated brake 36'.

While we have shown and described the preferred embodiments of our invention, it will be understood that the invention may be embodied otherwise than as herein specifically illustrated or described, and that certain changes in the form and arrangement of parts and in the specific manner of practicing the invention may be made without departing from the underlying ideas or principles of this invention within the scope of the appended claims.

What is claimed is:

1. In a hand tool having a rotatable member mounted for rotation thereon and a first passageway for the transmission of fluid pressure to said rotatable member for the rotation thereof; means for controlling the rotation of said rotatable member, comprising a brake member mounted for movement to engage said rotatable member for the braking thereof, a second passageway in fluid communication with said brake member for transmitting fluid pressure thereto for moving said brake member into engagement with said rotatable member ror the braking operation, and valve means operative to concurrently prevent the transmission of fluid pressure through said first passageway and permit the transmission of fluid pressure through said second passageway for the braking operation, said valve means being mounted on said hand tool and being operated manually.

2. In a fluid operated dental hand tool having a rotary member and a fluid passage for transmitting pressure fluid to said member for the operation thereof; valve means in said passage for controlling the flow of fluid to said memher to thereby control the operation of said member, means positioned adjacent said member and operable to apply a braking force to said member, said last mentioned means being operatively connected to said valve means and operable in response to the operation of said valve means for applying said braking force concurrently With the stopping of the flow of pressure fluid to said rotary member as a result or" said operation of said valve means.

3. In a fluid operated hand tool having a movable member and a fluid passage for transmitting pressure fluid to said member for the operation thereof; valve means in said passage movable into passage opening and closing positions for controlling the flow of said fluid to said member to thereby control the operation of said member, brake means positioned in operative relation to said member and operable to engage said member for the braking operation, and means operable in response to passage closing movement of said valve means to operate said brake means for the braking operation concurrently with the stopping of the flow of pressure fluid to said mem' er as a result of said closing movement of said valve means.

4. In a fluid operated dental hand tool having a rotary member and a fluid passage for transmitting pressure fluid to said member for the operation thereof; valve means in said passage movable into passage opening and closing positions for controlling the flow of said fluid to said member to thereby control the operation of said member, brake means positioned in operative relation to said member and operable to engage said member for the braking operation, and means operable in response to passage closing movement of said valve means to operate said brake means for the braking operation concurrently with the stopping of the flow of pressure fluid to said member as a result of said closing movement of said valve means.

5. In a fluid operated dental hand tool having a rotary member at one end thereof adapted to carry a cutting implement and a fluid passage for transmitting pressure fluid to said member for the operation thereof; valve means in said passage movable into passage opening and closing positions for controlling the flow of said fluid to said member to thereby control the operation of said member, brake means positioned in operative relation to said member and operable to engage said member for the braking operation, fluid passage means in fluid flow communication with said brake means for transmitting pressure fluid to said brake means for the operation thereof, and means operable in response to passage closing movement of said valve means to transmit pressure fluid through said fluid passage means to said brake means for the operation thereof concurrently with the stopping of the flow of pressure fluid to said member as a result of said closing movement of said valve means.

In a fluid operated dental hand tool having a rotary member at one end thereof adapted to carry a cutting implement and a fluid passage for transmitting pressure fluid to said member for the operation thereof; solenoid operated valve means in said passage movable into passage opening and closing positions for controlling the flow of said fluid to said member to thereby control the operation of said member, electrically operated brake means positioned in operative relation to said member and operable to engage said member for the braking operation, circuit means electrically interconnecting said brake means and said valve means, and switch means in said circuit means operable to simultaneously operate said valve means and said brake means for stopping the flow of pressure fluid to said member concurrently with the braking operation of said brake means.

7. In a dental hand tool having a rotary member and a first passage for the transmission of pressure fluid to said member for the operation thereof; means for controlling the rotation of said member comprising a brake member mounted for movement to engage said rotary member for the braking thereof, a second passage in fluid flow cornmunication with said brake member for transmitting pressure fluid thereto for moving said brake member into engagement With said rotary member for the braking operation, and valve means operatively connected to said first and second passages to concurrently prevent the transmission of pressure fluid through said first passage and permit the transmission of pressure fluid through said second passage for the braking operation.

8. In a fluid operated dental hand tool having a rotary member at one end thereof adapted to carry a cutting implement and a fluid passage for transmitting pressure fluid to said member for the operation thereof; brake means positioned in operative relation to said member and operable to engage said member for the braking operation, another fluid passage in fluid flow communication with said brake means for transmitting pressure fluid to said brake means for the operation thereof, solenoid operated valve means associated with each of said passages for controlling the flow of pressure fluid therethrough, said valve means including means for permitting the flow of fluid through one of said passages "while preventing the flow of fluid through the other of said passages, and electric means for operating said valve means to permit the flow of pressure fluid through said other passage for the braking operation concurrently With the stopping of the flow of pressure fluid through said first mentioned passage.

9. In a fluid operated dental hand tool having a rotary member at one end thereof adapted to carry a cutting implement and a fluid passage for transmitting pressure fluid to said member for the operation thereof; brake means positioned in operative relation to said member and operable to engage said member for the braking operation, another fluid passage in fluid flow communication With said brake means for transmitting pressure fluid to said brake means for the operation thereof, and valve means in fluid flow communication With each of said passages for diverting the flow of fiuid from said first men tioned passage to said other passage for the operation of said brake means concurrently With the stopping of the flow of fluid to said member.

10. In a fluid operated dental hand tool having a rotary member at one end thereof adapted to carry a cutting implement and a fluid passage for transmitting pressure fluid to said member for the operation thereof; solenoid operated valve means in said passage movable into passage opening and closing positions for controlling the flow of said fluid to said member to thereby control the operation of said member, electrically operated brake means positioned in operative relation to said member and operable to engage said member for the braking operation, circuit means electrically interconnecting said brake means and said valve means, and switch means in said circuit means operable to simultaneously operate said valve means and said brake means for stopping the flow of pressure fluid to said member concurrently with the braking operation of said brake means, said electrically operated brake means comprising an electromagnet having a core movable into engagement with said member and an electric winding surrounding said core and electrically connected to said switch means.

11. In a fluid operated dental hand tool having a rotary member at one end thereof adapted to carry a cutting implement and a fluid passage for transmitting pressure fluid to said member for the operation thereof; another fluid passage having an outlet opening positioned adiacent a part of said member, said part having opposite flat surfaces, and valve means in fluid flow communication with each of said passages for diverting the flow of fluid from said first mentioned passage to said other passage so hat fluid issuing from said outlet opening is directed against said fiat surfaces to stop the rotation of said member by the impact force of said issuing fluid on said flat surfaces concurrently with the stopping of the flow of fluid to said member through said first mentioned passage.

12. In a dental hand tool having a rotary member and a fluid passage for transmitting pressure fluid to said rotary member for the operation thereof; means for braking the rotational movement of said member comprising a movable diaphragm secured to said hand tool adjacent said rotary member, a brake member mounted on said diaphragm and movable therewith into egnagement with said rotary member for the braking thereof, and a fluid passage having an outlet opening at one side of said diaphragm for transmitting pressure fluid to said side of said diaphragm to move said diaphragm toward said rotary member and thereby move said brake member into engagement with said rotary member for the braking thereof.

a 13. In a fluid operated dental hand tool having a rotary member at one end thereof adapted to carry a cutting implement and a fluid passage for transmitting pressure fluid to said member for the operation thereof; a movable diaphragm secured to said hand tool adjacent said rotary member, a brake member mounted on said diaphragm and movable therewith into engagement with said rotary member for the braking thereof, another fluid passage having an outlet opening in fluid flow communication with one side of said diaphragm for transmitting pressure fluid to said side of said diaphragm to move said diaphragm toward said rotary member and thereby move said brake member into engagement with said rotary member for the braking thereof, and valve means in fluid flow communication with each of said passages for diverting the flow of fluid from said first mentioned passage to said other passage for moving said brake member into engagement with said rotary member to stop the rotation thereof concurrently with the stopping of the flow of fluid to said rotary member.

14. In a hand tool having a rotary member and a fluid passage for transmitting fluid pressure to said member for the rotation thereof; means for braking the rotational movement of said member comprising an electromagnetic brake member mounted adjacent said rotary member for movement into engagement with said rotary member for the braking thereof, an eiectric winding surrounding said brake member for providing an electromagnetic force to move said brake member into engagement with said rotary member for the braking operation, a solenoid valve for controlling the flow of pressure fluid to said fluid passage, said electrical winding being electrically connected to the coil of said solenoid valve, and switch means in circuit with said Winding for operating said winding and said coil of said solenoid valve to actuate said brake member for the braking operation simultaneousiy with the operation of said solenoid valve for shutting off the flow of fluid pressure to said rotary member.

15. In a fluid operated dental hand tool having a rotary member removably mounted thereon and a fluid passage for transmitting pressure fluid to said member for the operation thereof; a movable diaphragm secured to said hand tool adjacent said rotary member, a brake member mounted on said diaphragm and movable therewith into engagement with said rotary member for the braking thereof, another fluid passage having an outlet opening in fluid flow communication with one side of said diaphragm for transmitting pressure fluid to said side of said diaphragm to move said diaphragm toward said rotary member and thereby move said brake member into engagement with said rotary member for the braking thereof, and valve means in fluid flow communication with each of said passages for diverting the flow of fluid from said first mentioned passage tosaid other passage for moving said brake member into engagement with said rotary member to stop the rotation thereof concurrently with the stopping of the flow of fluid to said rotary member, said brake member having a passage therethrough with an opening adjacent said rotary member to permit a tool to be inserted through said passage for engaging said rotary member to remove it from the hand tool.

References Cited in the file of this patent UNITED STATES PATENTS 1,040,424 Salt Oct. 8, 1912 2,206,723 Graham et a1. July 2, 1940 2,547,660 Prince Apr. 3, 1951 2,664,632 Norlen Jan. 5, 1954 

